make additional properties nullable

Author: leo-schick

tap_zendesk/schemas/archive/talk_availabilities.json

@@ -2,7 +2,10 @@
     "type": ["object"],
     "properties": {
         "agent_id": {
-            "type": ["integer"]
+            "type": [
+                "integer",
+                "null"
+            ]
         },
         "agent_state": {
             "type": [

tap_zendesk/schemas/talk_calls.json

@@ -33,7 +33,7 @@
             "enum": ["queue", "web widget"]
         },
         "completion_status": {
-            "type": ["string"],
+            "type": ["string", "null"],
             "description": "Status of the call",
             "enum": ["completed", "abandoned_in_queue", "abandoned_in_ivr", "abandoned_in_voicemail", "abandoned_on_hold", "pending_voicemail"]
         },